diff options
Diffstat (limited to 'vendor/github.com/hashicorp/go-plugin/grpc_broker.go')
| -rw-r--r-- | vendor/github.com/hashicorp/go-plugin/grpc_broker.go | 455 |
1 files changed, 455 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/go-plugin/grpc_broker.go b/vendor/github.com/hashicorp/go-plugin/grpc_broker.go new file mode 100644 index 000000000..49fd21c61 --- /dev/null +++ b/vendor/github.com/hashicorp/go-plugin/grpc_broker.go @@ -0,0 +1,455 @@ +package plugin + +import ( + "context" + "crypto/tls" + "errors" + "fmt" + "log" + "net" + "sync" + "sync/atomic" + "time" + + "github.com/oklog/run" + "google.golang.org/grpc" + "google.golang.org/grpc/credentials" +) + +// streamer interface is used in the broker to send/receive connection +// information. +type streamer interface { + Send(*ConnInfo) error + Recv() (*ConnInfo, error) + Close() +} + +// sendErr is used to pass errors back during a send. +type sendErr struct { + i *ConnInfo + ch chan error +} + +// gRPCBrokerServer is used by the plugin to start a stream and to send +// connection information to/from the plugin. Implements GRPCBrokerServer and +// streamer interfaces. +type gRPCBrokerServer struct { + // send is used to send connection info to the gRPC stream. + send chan *sendErr + + // recv is used to receive connection info from the gRPC stream. + recv chan *ConnInfo + + // quit closes down the stream. + quit chan struct{} + + // o is used to ensure we close the quit channel only once. + o sync.Once +} + +func newGRPCBrokerServer() *gRPCBrokerServer { + return &gRPCBrokerServer{ + send: make(chan *sendErr), + recv: make(chan *ConnInfo), + quit: make(chan struct{}), + } +} + +// StartStream implements the GRPCBrokerServer interface and will block until +// the quit channel is closed or the context reports Done. The stream will pass +// connection information to/from the client. +func (s *gRPCBrokerServer) StartStream(stream GRPCBroker_StartStreamServer) error { + doneCh := stream.Context().Done() + defer s.Close() + + // Proccess send stream + go func() { + for { + select { + case <-doneCh: + return + case <-s.quit: + return + case se := <-s.send: + err := stream.Send(se.i) + se.ch <- err + } + } + }() + + // Process receive stream + for { + i, err := stream.Recv() + if err != nil { + return err + } + select { + case <-doneCh: + return nil + case <-s.quit: + return nil + case s.recv <- i: + } + } + + return nil +} + +// Send is used by the GRPCBroker to pass connection information into the stream +// to the client. +func (s *gRPCBrokerServer) Send(i *ConnInfo) error { + ch := make(chan error) + defer close(ch) + + select { + case <-s.quit: + return errors.New("broker closed") + case s.send <- &sendErr{ + i: i, + ch: ch, + }: + } + + return <-ch +} + +// Recv is used by the GRPCBroker to pass connection information that has been +// sent from the client from the stream to the broker. +func (s *gRPCBrokerServer) Recv() (*ConnInfo, error) { + select { + case <-s.quit: + return nil, errors.New("broker closed") + case i := <-s.recv: + return i, nil + } +} + +// Close closes the quit channel, shutting down the stream. +func (s *gRPCBrokerServer) Close() { + s.o.Do(func() { + close(s.quit) + }) +} + +// gRPCBrokerClientImpl is used by the client to start a stream and to send +// connection information to/from the client. Implements GRPCBrokerClient and +// streamer interfaces. +type gRPCBrokerClientImpl struct { + // client is the underlying GRPC client used to make calls to the server. + client GRPCBrokerClient + + // send is used to send connection info to the gRPC stream. + send chan *sendErr + + // recv is used to receive connection info from the gRPC stream. + recv chan *ConnInfo + + // quit closes down the stream. + quit chan struct{} + + // o is used to ensure we close the quit channel only once. + o sync.Once +} + +func newGRPCBrokerClient(conn *grpc.ClientConn) *gRPCBrokerClientImpl { + return &gRPCBrokerClientImpl{ + client: NewGRPCBrokerClient(conn), + send: make(chan *sendErr), + recv: make(chan *ConnInfo), + quit: make(chan struct{}), + } +} + +// StartStream implements the GRPCBrokerClient interface and will block until +// the quit channel is closed or the context reports Done. The stream will pass +// connection information to/from the plugin. +func (s *gRPCBrokerClientImpl) StartStream() error { + ctx, cancelFunc := context.WithCancel(context.Background()) + defer cancelFunc() + defer s.Close() + + stream, err := s.client.StartStream(ctx) + if err != nil { + return err + } + doneCh := stream.Context().Done() + + go func() { + for { + select { + case <-doneCh: + return + case <-s.quit: + return + case se := <-s.send: + err := stream.Send(se.i) + se.ch <- err + } + } + }() + + for { + i, err := stream.Recv() + if err != nil { + return err + } + select { + case <-doneCh: + return nil + case <-s.quit: + return nil + case s.recv <- i: + } + } + + return nil +} + +// Send is used by the GRPCBroker to pass connection information into the stream +// to the plugin. +func (s *gRPCBrokerClientImpl) Send(i *ConnInfo) error { + ch := make(chan error) + defer close(ch) + + select { + case <-s.quit: + return errors.New("broker closed") + case s.send <- &sendErr{ + i: i, + ch: ch, + }: + } + + return <-ch +} + +// Recv is used by the GRPCBroker to pass connection information that has been +// sent from the plugin to the broker. +func (s *gRPCBrokerClientImpl) Recv() (*ConnInfo, error) { + select { + case <-s.quit: + return nil, errors.New("broker closed") + case i := <-s.recv: + return i, nil + } +} + +// Close closes the quit channel, shutting down the stream. +func (s *gRPCBrokerClientImpl) Close() { + s.o.Do(func() { + close(s.quit) + }) +} + +// GRPCBroker is responsible for brokering connections by unique ID. +// +// It is used by plugins to create multiple gRPC connections and data +// streams between the plugin process and the host process. +// +// This allows a plugin to request a channel with a specific ID to connect to +// or accept a connection from, and the broker handles the details of +// holding these channels open while they're being negotiated. +// +// The Plugin interface has access to these for both Server and Client. +// The broker can be used by either (optionally) to reserve and connect to +// new streams. This is useful for complex args and return values, +// or anything else you might need a data stream for. +type GRPCBroker struct { + nextId uint32 + streamer streamer + streams map[uint32]*gRPCBrokerPending + tls *tls.Config + doneCh chan struct{} + o sync.Once + + sync.Mutex +} + +type gRPCBrokerPending struct { + ch chan *ConnInfo + doneCh chan struct{} +} + +func newGRPCBroker(s streamer, tls *tls.Config) *GRPCBroker { + return &GRPCBroker{ + streamer: s, + streams: make(map[uint32]*gRPCBrokerPending), + tls: tls, + doneCh: make(chan struct{}), + } +} + +// Accept accepts a connection by ID. +// +// This should not be called multiple times with the same ID at one time. +func (b *GRPCBroker) Accept(id uint32) (net.Listener, error) { + listener, err := serverListener() + if err != nil { + return nil, err + } + + err = b.streamer.Send(&ConnInfo{ + ServiceId: id, + Network: listener.Addr().Network(), + Address: listener.Addr().String(), + }) + if err != nil { + return nil, err + } + + return listener, nil +} + +// AcceptAndServe is used to accept a specific stream ID and immediately +// serve a gRPC server on that stream ID. This is used to easily serve +// complex arguments. Each AcceptAndServe call opens a new listener socket and +// sends the connection info down the stream to the dialer. Since a new +// connection is opened every call, these calls should be used sparingly. +// Multiple gRPC server implementations can be registered to a single +// AcceptAndServe call. +func (b *GRPCBroker) AcceptAndServe(id uint32, s func([]grpc.ServerOption) *grpc.Server) { + listener, err := b.Accept(id) + if err != nil { + log.Printf("[ERR] plugin: plugin acceptAndServe error: %s", err) + return + } + defer listener.Close() + + var opts []grpc.ServerOption + if b.tls != nil { + opts = []grpc.ServerOption{grpc.Creds(credentials.NewTLS(b.tls))} + } + + server := s(opts) + + // Here we use a run group to close this goroutine if the server is shutdown + // or the broker is shutdown. + var g run.Group + { + // Serve on the listener, if shutting down call GracefulStop. + g.Add(func() error { + return server.Serve(listener) + }, func(err error) { + server.GracefulStop() + }) + } + { + // block on the closeCh or the doneCh. If we are shutting down close the + // closeCh. + closeCh := make(chan struct{}) + g.Add(func() error { + select { + case <-b.doneCh: + case <-closeCh: + } + return nil + }, func(err error) { + close(closeCh) + }) + } + + // Block until we are done + g.Run() +} + +// Close closes the stream and all servers. +func (b *GRPCBroker) Close() error { + b.streamer.Close() + b.o.Do(func() { + close(b.doneCh) + }) + return nil +} + +// Dial opens a connection by ID. +func (b *GRPCBroker) Dial(id uint32) (conn *grpc.ClientConn, err error) { + var c *ConnInfo + + // Open the stream + p := b.getStream(id) + select { + case c = <-p.ch: + close(p.doneCh) + case <-time.After(5 * time.Second): + return nil, fmt.Errorf("timeout waiting for connection info") + } + + var addr net.Addr + switch c.Network { + case "tcp": + addr, err = net.ResolveTCPAddr("tcp", c.Address) + case "unix": + addr, err = net.ResolveUnixAddr("unix", c.Address) + default: + err = fmt.Errorf("Unknown address type: %s", c.Address) + } + if err != nil { + return nil, err + } + + return dialGRPCConn(b.tls, netAddrDialer(addr)) +} + +// NextId returns a unique ID to use next. +// +// It is possible for very long-running plugin hosts to wrap this value, +// though it would require a very large amount of calls. In practice +// we've never seen it happen. +func (m *GRPCBroker) NextId() uint32 { + return atomic.AddUint32(&m.nextId, 1) +} + +// Run starts the brokering and should be executed in a goroutine, since it +// blocks forever, or until the session closes. +// +// Uses of GRPCBroker never need to call this. It is called internally by +// the plugin host/client. +func (m *GRPCBroker) Run() { + for { + stream, err := m.streamer.Recv() + if err != nil { + // Once we receive an error, just exit + break + } + + // Initialize the waiter + p := m.getStream(stream.ServiceId) + select { + case p.ch <- stream: + default: + } + + go m.timeoutWait(stream.ServiceId, p) + } +} + +func (m *GRPCBroker) getStream(id uint32) *gRPCBrokerPending { + m.Lock() + defer m.Unlock() + + p, ok := m.streams[id] + if ok { + return p + } + + m.streams[id] = &gRPCBrokerPending{ + ch: make(chan *ConnInfo, 1), + doneCh: make(chan struct{}), + } + return m.streams[id] +} + +func (m *GRPCBroker) timeoutWait(id uint32, p *gRPCBrokerPending) { + // Wait for the stream to either be picked up and connected, or + // for a timeout. + select { + case <-p.doneCh: + case <-time.After(5 * time.Second): + } + + m.Lock() + defer m.Unlock() + + // Delete the stream so no one else can grab it + delete(m.streams, id) +} |